Torrent 6200 LTE eNB Test System

LTE eNB Testing

The 6200 is our forthcoming solution for LTE over the air testing for eNBs, and also for UEs. In terms of functionality, it is largely a superset of the 6100, but with added over the air test functionality.

The 6200 is based on the hardware, software, and firmware used in our Torrent 7240 for WiMAX testing, and we look forward to announcing its availibility soon.

Solution: The Torrent 6200

The Torrent 6200 is a Linux based real time system for testing 3GPP LTE eNBs (eNodeBs) and UEs both functionally and from a performance, troubleshooting, and optimization standpoint. It is well suited for both initial development of such systems, as well as for verification of them in a network operator lab.

The 6200 builds on gournd breaking technology devloped for its WiMAX countepart (the Torrent 7240), that allowed for 4000+ mobiles on a single channel.

The 6200 is scheduled for release in 1Q16, but initial interoperability tests at 20MHz bandwidth with a commercial eNB have been successful and showed the folloing results:

Torrent 6200 consists of several high performance server applications that together can emulate a complete LTE network from the standpoint of the eNB or UE:

This central controller for the system, called the CS-6200, automatically configures, starts, and directs the traffic servers in the system to run tests as directed by the user through a GUI interface.

The MTS-6200 traffic server authentically simulates thousands of UEs per channel. The optional ENB-6200 emulates an eNB for UE testing purposes. The MME-6200 simulates the Mobility Management Entity, or alternatively can be replaced with the MME under test. Similarly the SGW-6200 and PGW-6200 simulate the Serving Gateway and PDN Gateways respectively, and like the MME-6200 may be replaced with their counterparts under test as desired. Finally, the NTS-6200 provides a convenient aggregation of network servers (MMS, HTTP, FTP, SMTP, DHCP, PoC, WAP, etc.) as well as acting as a PCRF, CGF, and Radius Server.

Key System Features

Realistic Mobile Simulation
A central feature of the system is that it is realistic, and simulates mobiles and the application data traffic that they generate as precisely as possible. In particualr, mobiles are stateful and have their own network stacks built-in.

Realistic Network Simulation
Because the entire network around the system under test is authentically simulated, complex call scenarios can easily be created. This kind of test bed realism has allowed our users to recreate field issues that otherwise were not reproducible in the lab [i.e. this has been the case with our other Torrent products which use very similar technology].

Linux Based
All of our systems are Linux based and the Torrent 6200 is no exception. This provides our users with a state of the art operating system, that they are almost invariably familiar with.

High Speed Dataplane Architecture
The Torrent 6200 was designed from the ground up for very high data plane throughput. In the latest release, we've achieved our goal of allowing for line rate streaming of arbitrary traffic types, inlcuding video and voice at near line rates and with hardly any loss. With our ability to stream linearly, and also to generate complex control plane traffic this provides for rather comprehensive stress for the system under test.

Highly Parallel Simulation
Parallelism is supported on numerous levels. Typically, parallelism is created when more than one test case is executed at the same time during a test suite of by hand. However, parallelism can be extended down to the individual mobile subscriber as illustrated in the following mobile script:

Full Automation Support
Test cases may be fully automated and allow the end user to interact with the system under test via ssh, telent, ftp, etc. through an Expect style interface.

Linear Scalability
Any traffic profile can be scaled linearly by simply adding more computing hardware, and this can be accomplished wihout having to rewrite or otherwise modify test cases.

Ease of Use
The Torrent 6200 features a simple installation process and intuitive multi-user GUI. And it does not require programming knowledge to operate. Thus the learning curve is rather minimal - the philosophy being we want you to concentrate on your work, and not on how to run the test system.QoE Characterization
A key aspect of the system is that it allows the end subscriber's experience to be characterized through a number of key performance indicators (KPIs). For each KPI, the system tracks not only the mean and standard deviation, but a complete high resolution histogram as shown below for MMS:

Histograms are particularly useful for studying the effect of background traffic on interactive traffic, especially under heavy loads.

QoS You Can See and Hear
A unique feature of the system is that it allows any PC to connect to one of the simulated mobiles and relay all of its traffic through it. In this way, the performance of streaming media applications such as YouTube can be subjectively evaluated under different traffic conditions.

Detailed Hierarchical Statistics
Hundreds of statistics are captured by the system on both the MTS and NTS and they are organized in a hierarchical manner to allow both the big picture and the finer details to be seen more clearly. These statistics may be examined in real time by test cases, or they may be exported in build via CSV file to Excel. Additionally KPIs may be graphed dynamically.

Configurable Messaging
The structure and content of messages can be configured via XML templates which may be edited via the GUI.Network Service Assurance
While the Torrent system was originally designed for lab use, it may also be used to perform in-service networkmonitoring. For example, network entry, handover and data path functionality can be spot-checked periodically and an alarm raised if failures are detected.

Extensive Dataplane Support
Dataplane functionality is seamlessly and naturally integrated into the system. Each mobile directly supports: IP, TCP, UDP, HTTP, WAP, MMS, PTT (PoC), SIP, RTP, RTCP, FTP, SMTP, POP3, ICMP, DHCP, and DNS. This in addition to the new STS based streaming capabilities that allow for streaming modern, popular traffic types like YouTube and Netflix.